Two air handlers one compressor

I recently purchased an 80’s apartment converted to condo. Two story with separate air handlers up and down. They each have a thermostat and are not connected together in any way other than using the same compressor for ac. As you can imagine this has issues and needs help. It seems likely it used to be some sort of master/slave electrically and for whatever reason was converted to this. I called a couple local hvac places and they don’t seem like they really want to get involved.

I’m looking for some guidance on where to point a contractor to resolve this.

You shouldn’t be pointing the contractor in any direction.

2 separate condos need 2 separate Systems!

Originally Posted by gswyman

I recently purchased an 80’s apartment converted to condo. Two story with separate air handlers up and down. They each have a thermostat and are not connected together in any way other than using the same compressor for ac. As you can imagine this has issues and needs help. It seems likely it used to be some sort of master/slave electrically and for whatever reason was converted to this. I called a couple local hvac places and they don’t seem like they really want to get involved.

I’m looking for some guidance on where to point a contractor to resolve this.

Lennox used to make a system like that. 2 stage outdoor unit, zone board, and 2 indoor coils/air handlers. Got a model # of the outdoor unit?

Originally Posted by FlyersFan

Lennox used to make a system like that. 2 stage outdoor unit, zone board, and 2 indoor coils/air handlers. Got a model # of the outdoor unit?

Daiken Model # DX14SA0301AC As much as I would like for this to be an elegant solution, I have a feeling it isn’t. When either air handler turns on the ac it feeds freon to both units. The one that didn’t turn on the compressor doesn’t have the fan running so it freeze’s or starts to freeze. These systems were designed 40 years ago for what was then an apartment. At some point their had to interaction between the two air handlers electrically.

More than likely it was originally a system like I described, Lennox just happened to be the most popular around here. That being said, what you currently have is a mess, and you’re probably about to spend a good deal of cash getting it replaced with the correct equipment. 2 air handlers are going to require to separate line sets going outside to either 2 separate condensers or a multizone mini split. Ask around to see if any friends, coworkers, etc. have any contractor recommendations or check the contractor locator on this site for someone that’s close by.

Bigger HVAC companies that push a lot of advertising tend to be more sales driven instead of “finding a good solution” driven (at least in my neck of the woods), and you’re going to need someone who can really look at what you have to come up with a good solution. Almost not joking when I say try to find someone with a tech that’s been in a service truck for 20 years.

Originally Posted by FlyersFan

More than likely it was originally a system like I described, Lennox just happened to be the most popular around here. That being said, what you currently have is a mess, and you’re probably about to spend a good deal of cash getting it replaced with the correct equipment. 2 air handlers are going to require to separate line sets going outside to either 2 separate condensers or a multizone mini split. Ask around to see if any friends, coworkers, etc. have any contractor recommendations or check the contractor locator on this site for someone that’s close by.

Bigger HVAC companies that push a lot of advertising tend to be more sales driven instead of “finding a good solution” driven (at least in my neck of the woods), and you’re going to need someone who can really look at what you have to come up with a good solution. Almost not joking when I say try to find someone with a tech that’s been in a service truck for 20 years.

About what I thought. Thanks for taking the time.

Lennox had the HS12 in the 70s. 2 compressors and then can be hooked up to 2 indoor units.

It’s done with refrigeration systems all the time but not the way you discribed

There is a real good chance this system was installed and worked proper at one time. Then someone who did not know what they were doing changed some wiring and that is why you have what you have now.